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Grain yields and calcium status in maize hybrids under neutral and acid soil conditions

Calcium (Ca) is one of the essential elements for plant growth and development. Plant Ca contents differ very widely depending on soil properties. Also, soil and plant Ca status are considerable factors of the other essential elements availability. For example, it was found nutritional disorders of seed-corn growth in the Eastern Croatia and some examples of these disorders were in connection with low Ca concentrations or Ca oversupply. As inheritance is also included as a factor of plant nutrition, we tested nutritional status of maize hybrids which were grown on two soil types. Ten maize hybrids were grown on neutral and acid soil (Osijek eutrical cambisol and Durdanci stagnosol, respectively) during the growing season of 1989. The field trials conducted in three replications. Gross of each plot of hybrid was 7.16 m2 (one 10-m row). Corn was sown manually (interrow spacing 70 cm, spacing in row 22.5 cm) at planned density 63 500/ha. The ear-leaf for chemical analysis was taken at beginning of silking stage (the second decade of July). Grain yields were calculated on theoretical plant density and 14% moisture basis. Average grain yield of maize was considerably higher on eutric cambisol (9.54 t ha-1) in comparison to stagnosol (6.74 t ha-1). Mean ear-leaf Ca status were 1.17% Ca and 0.48% Ca for eutric cambisol and stagnosol, respectively. Considerable differences of grain yields and ear-leaf Ca status were found among tested hybrids as follows: from 7.62 to 12.19 t ha-1 (eutrical cambisol) and from 3.66 to 9.44 t ha-1 (stagnosol), from 1.04 to 1.34 % Ca (eutrical cambisol) and from 0.36 to 0.60 % Ca (stagnosol), respectively. However, low connection was found between ear-leaf Ca status and grain yields. Os84-15xOs87-24 hybrid was the first-ranged concerning grain yield of two trials (9.96 t ha-1), while by Os86-92xOs87-57 hybrid was achieved the lowest grain yield (5.64 t ha-1). Concerning tolerance to acid soil stress, the hybrids Os84-15xOs87-24 and Os86-92xOs87-56 could be designated as more tolerant because their grain yields were considerably higher (for 40% and for 16%, respectively) in comparison with average of ten hybrids. Also, Os86-92xOs87-57 was the most sensitive to acid soil because its yield was 60% lower in comparison with the most tolerant hybrid (Table 1). Mg status among ten tested hybrids were in range from 0.43 to 0.47% Mg and from 0.29 to 0.40% Mg, for cambisol and stagnosol, respectively. Acidity is a major degradation factor of soil and covers extensive areas in the tropical and temperate climate. Plant growth-limiting factors in acid soils include deficiencies (N, P, Ca, Mg, Mo, Zn) and toxicities (Al, Mn, Fe, H) of elements. Testing of maize genotypes to acid soil stress were made seriously under conditions of acid soils in the Brazilian savanna (Cerrado) and the high yielding aluminum tolerant double-cross myize hybrids BR 201, BR 205 and BR 206 were developed. By our testing in acid soil containing high levels of exhangeable Al, grain yields of 24 maize hybrids yielded from 1.42 to 3.40 t ha-1. Considerable differences of grain yields and Ca status were found among maize hybrids under identical soil conditrions, as well as between two tested soils. Similar investigations and their application could be to contribute achieving of the higher yields on the soils of lower fertility.

Maize; Hybrids; Calcium; Soil

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